Dark matter is thought to be all around us, yet scientists can't see it, touch it, or even figure out what it is.

Now four astronomers who helped befuddle the world by discovering evidence for dark matter have won a prestigious cosmology prize. Scientists infer the existence of dark matter by its gravitational influence on the regular, visible matter around it.

The scientists will share the $500,000 purse that comes with the 2011 Cosmology Prize of the Peter and Patricia Gruber Foundation.

The winners are: University of California, Berkeley, astronomer Marc Davis; George Efstathiou, the director of the Kavli Institute for Cosmology in Cambridge, England; Carlos Frenk, the director of the Institute for Computational Cosmology at Durham University in England; and Simon White, a director of the Max Planck Institute for Astrophysics in Garching, Germany.

The researchers created key computer simulations more than 20 years ago that mapped the large-scale distribution of matter in the universe. The simulations were enough to convince most experts of the existence of dark matter, and set off a so-far fruitless search to find out what it is.

In 1981, while he was a young professor of astronomy at the Harvard-Smithsonian Center for Astrophysics (CfA), Davis surveyed 2,400 galaxies at various distances, and discovered that the universe wasn't just a uniform scattering of galaxies, but a cosmic web' of galaxies grouped into filaments separated by vast voids. [Video: Dark Matter in 3D]

"At the time, nobody had any idea what the large scale distribution of matter was, and mostly we didn’t think about it," Davis said in a statement. "I soon saw that the best mathematical model of the Big Bang we had was wrong, there was a complete disconnect between our CfA observations and the theory."

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While the search for dark matter since then has been frustrating, since no plausible particle responsible for dark matter has yet been detected by scientists, the researchers said the discovery was exhilarating, too.

"Boy, that was just a fun thing to do, we really had a great time, we loved it," Davis said of his collaboration with Efstathiou, Frenk and White, who together were called the DEFW team, or the Gang of Four.

"Nobody yet knows what dark matter or dark energy are," according to a Gruber Foundation statement. "Today the match between observation and theory indicates that the universe is composed of 4.6 percent 'ordinary' matter, 23.3 percent dark matter, and 72.1 percent dark energy. Numerical simulations of the kind pioneered by DEFW show that a universe with this astonishingly precise yet remarkably strange composition does indeed develop structures which are a close match to those we see around us."

Step right up and click inside to see dark matter revealed! Scientists think the mysterious substance makes up most of the mass in the universe — but because it doesn't give off light, visible proof of its existence is elusive. Theory suggests that the invisible stuff acts as gravitational glue that keeps the stars and galaxies from flying apart. Now, armed with powerful telescopes, tricky lenses and fast computers, scientists are at last bringing the evidence of dark matter to light.

For example, in this image, the yellowish galaxy cluster in the middle serves as a gravitational lens that bends the light of even more distant galaxies. Those galaxies appear as distorted blue streaks surrounding the cluster. Scientists can analyze the distortions to determine how dark matter is distributed in the cluster.

Click to see what else scientists have found out about dark matter.

— John Roach, msnbc.com contributor

Super clumpy

NASA / ESA

Dark matter, it turns out, may be rather clumpy stuff. This image shows a galaxy supercluster -- a grouping of hundreds of interacting galaxies -- about 2.6 billion light years from Earth. The bright blue spots are the visible galaxies, superimposed over magenta-tinted clumps that represent a detailed map of dark matter. The map was created by inferring how the light from even more distant galaxies is bent as it passes through the gravitational field of the supercluster, which is called Abell 901/902. Astronomers found that the supercluster's galaxies lie within the clumps of dark matter, and the irregular shapes of the clumps match the distribution of the galaxies.

This 3-D map of the large-scale distribution of dark matter in the universe provides compelling evidence that the invisible stuff serves as the scaffolding upon which the stars and galaxies are hung. The map reveals a network of filaments that grow over time and intersect in massive structures at places where galaxy clusters are located. To make the map, astronomers used ground and space telescopes to determine the shape of half a million distant galaxies. This galactic light was bent and warped by the gravity of other galaxies as it traveled to the telescopes. By analyzing the shapes of these distant galaxies, astronomers were able infer the distribution of dark matter.

Bullet proof

Parsons

For proof that dark matter really exists, scientists turn to this image of a collision between two massive galaxy clusters that contains a bullet-shaped cloud of superheated gas. Theory suggests that during such a collision, a type of cosmic air resistance should slow down the hefty hot gas — but not the dark matter. That's what this image shows. The hot gas, pictured in red, is separated by the dark matter, pictured in blue. Scientists say the image serves as strong evidence that dark matter really does exist.

Train wreck

Prof. Rodolfo Coria / Ap

A massive collision of galaxy clusters about 3 billion years ago has proven to be a train wreck of sorts for dark matter theory. The prevailing theory suggests that the force of gravity should keep dark matter and galaxies together even during violent collisions, but that hot gas should lag behind due to the cosmic equivalent of air resistance. This image, however, shows the dark matter (blue) separated from most of the galaxies (yellow and orange). Scientists speculate that a gravitational slingshot effect may have separated the galaxies from the dark matter, or that the dark matter is interacting with some force other than gravity. Neither explanation fits well with existing theory. A third possibility is that the observations and calculations are off. Further research may yield an answer.

Some rings signify marriage, others a Super Bowl victory. This one may signify that dark matter exists. Astronomers made this composite image of a ghostly ring of apparent dark matter (mapped in blue) around a cluster of galaxies about 5 billion light years away. Computer simulations of the ancient galactic collision that created the cluster provide clues to how the ring formed. During the smash-up, dark matter fell to the center of the combined cluster and then started to slosh back out toward the edges. But the pull of gravity caused the dark matter to slow and pile up like cars speeding into a traffic jam on the freeway.

Cold or warm?

Science

Assuming dark matter does exist, is it cold or warm? If some of the universe's earliest stars can be found, computer simulations suggest the issue could be resolved. Slow-moving particles of cold dark matter would have caused single, massive stars to form in isolation. Faster-moving particles of warm dark matter, in contrast, would have caused the stars of differing sizes to form on long, thin filaments of dark matter — as pictured here. Since small stars are long-lived, they may still be lurking in our universe. Scientists hope to find them with new telescopes.

Southern stargazing

Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them.
(Y. Beletsky / ESO)
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A balloon's view

Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich.
(Kyle Moroney / AP)
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Spacemen at work

Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment.
(NASA)
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Special delivery

The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps.
(NASA)
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Accidental art

A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288.
(NASA / ESA)
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Supersonic test flight

A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

Red lagoon

The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes.
(ESO/VPHAS team)
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Fire on the mountain

This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people.
(NASA via AP)
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Where stars are born

An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues.
(NASA / JPL-Caltech)
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A long, long time ago...

This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang.
(NASA / NASA via AFP - Getty Images)
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Frosty halo

Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.